Thermco50 Cobalt-Base Heat Resistant Alloy UMCo-50
UMCo-50 is a cobalt-chromium-iron heat-resistant alloy with good
resistance to thermal shock, oxidatoin, and corrosion, It has great strength against sulfur-and vanadium-attacks. UmCo-50
has higher melting point compared to other cobalt based or nickel
based heat-resistant alloys.
For example, the alloy used for skid rails at a steel mill
undergoes regular use at 1350°C,so other alloys could not be used
due to their low melting point in the application related to heat
treatments and furnaces. But UMCo-50 shows successful results.
Chemical Composition (%, EN 10295)
| C | Si | Mn | P | S | Cr | Mo | Ni | Nb | Co | Fe |
| 0.05-0.25 | 0.50-1.50 | 1.5 | 0.04 | 0.03 | 27-30 | 0.50 | 4.0 | 0.50 | 48-52 | Balance |
Equal grades
Thermco50, W.Nr. 2.4778, Co50, G-CoCr28
Characteristics
High Temperature Resistance, Thermal Shock Resistance , Wear
Resistance
Higher melting points than other cobalt based and nickel based
alloys (1380 -1395 °C)
Corrosion resistant in Sparse sulfuric acid and boiling nitric acid
and corrosion rapidly in hydrochloric acid
Shock Resistances
Since thermal shock resistance was given first priority when
developing UMCo-50, this alloy shows far more outstanding thermal
shock resistance than the popularly used 25Cr-20Ni stainless steel.
For example, even after repeating the heating and cooling cycle
(1000-water cooling-7 seconds) for 500 times, no cracking occurred.
As a practical example, the alloy was used for four and a half
years as a tray which was heated up to 1000 in a heavy oil furnace
to quench various quenching agents. Hardly any cracking occurred in
UMCo-50, whereas the 25Cr-12Ni alloys were able to be used for only
8 months in average.
Available forms
Rods, forgings, seamless pipes, tube, etc
